CodePen Embed - Fancy Slider

<!-- 
Please note, that you can apply .m--global-blending-active to .fnc-slider 
to enable blend-mode for all background-images or apply .m--blend-bg-active
to some specific slides (.fnc-slide). It's disabled by default in this demo,
because it requires specific images, where more than 50% of bg is transparent or monotone
-->
<div class="demo-cont">
  <!-- slider start -->
  <div class="fnc-slider example-slider">
    <div class="fnc-slider__slides">
      <!-- slide start -->
      <div class="fnc-slide m--blend-green m--active-slide">
        <div class="fnc-slide__inner">
          <div class="fnc-slide__mask">
            <div class="fnc-slide__mask-inner"></div>
          </div>
          <div class="fnc-slide__content">
            <h2 class="fnc-slide__heading">
              <div class="fnc-slide__heading-line">
                <span>Black</span>
              </div>
              <div class="fnc-slide__heading-line">
                <span>Widow</span>
              </div>
            </h2>
            <button type="button" class="fnc-slide__action-btn">
              Credits
              <span data-text="Credits">Credits</span>
            </button>
          </div>
        </div>
      </div>
      <!-- slide end -->
      <!-- slide start -->
      <div class="fnc-slide m--blend-dark">
        <div class="fnc-slide__inner">
          <div class="fnc-slide__mask">
            <div class="fnc-slide__mask-inner"></div>
          </div>
          <div class="fnc-slide__content">
            <h2 class="fnc-slide__heading">
              <div class="fnc-slide__heading-line">
                <span>Captain</span>
              </div>
              <div class="fnc-slide__heading-line">
                <span>America</span>
              </div>
            </h2>
            <button type="button" class="fnc-slide__action-btn">
              Credits
              <span data-text="Credits">Credits</span>
            </button>
          </div>
        </div>
      </div>
      <!-- slide end -->
      <!-- slide start -->
      <div class="fnc-slide m--blend-red">
        <div class="fnc-slide__inner">
          <div class="fnc-slide__mask">
            <div class="fnc-slide__mask-inner"></div>
          </div>
          <div class="fnc-slide__content">
            <h2 class="fnc-slide__heading">
              <div class="fnc-slide__heading-line">
                <span>Iron</span>
              </div>
              <div class="fnc-slide__heading-line">
                <span>Man</span>
              </div>
            </h2>
            <button type="button" class="fnc-slide__action-btn">
              Credits
              <span data-text="Credits">Credits</span>
            </button>
          </div>
        </div>
      </div>
      <!-- slide end -->
      <!-- slide start -->
      <div class="fnc-slide m--blend-blue">
        <div class="fnc-slide__inner">
          <div class="fnc-slide__mask">
            <div class="fnc-slide__mask-inner"></div>
          </div>
          <div class="fnc-slide__content">
            <h2 class="fnc-slide__heading">
              <div class="fnc-slide__heading-line">
                <span>Thor</span>
              </div>
              <div class="fnc-slide__heading-line">
                <span>Just Thor</span>
              </div>
            </h2>
            <button type="button" class="fnc-slide__action-btn">
              Credits
              <span data-text="Credits">Credits</span>
            </button>
          </div>
        </div>
      </div>
      <!-- slide end -->
    </div>
    <nav class="fnc-nav">
      <div class="fnc-nav__bgs">
        <div class="fnc-nav__bg m--navbg-green m--active-nav-bg"></div>
        <div class="fnc-nav__bg m--navbg-dark"></div>
        <div class="fnc-nav__bg m--navbg-red"></div>
        <div class="fnc-nav__bg m--navbg-blue"></div>
      </div>
      <div class="fnc-nav__controls">
        <button class="fnc-nav__control">
          Black Widow
          <span class="fnc-nav__control-progress"></span>
        </button>
        <button class="fnc-nav__control">
          Captain America
          <span class="fnc-nav__control-progress"></span>
        </button>
        <button class="fnc-nav__control">
          Iron Man
          <span class="fnc-nav__control-progress"></span>
        </button>
        <button class="fnc-nav__control">
          Thor
          <span class="fnc-nav__control-progress"></span>
        </button>
      </div>
    </nav>
  </div>
  <!-- slider end -->
  <div class="demo-cont__credits">
    <div class="demo-cont__credits-close"></div>
    <h2 class="demo-cont__credits-heading">Made by</h2>
    <img src="//s3-us-west-2.amazonaws.com/s.cdpn.io/142996/profile/profile-512_5.jpg" alt="" class="demo-cont__credits-img" />
    <h3 class="demo-cont__credits-name">Nikolay Talanov</h3>
    <a href="https://codepen.io/suez/" target="_blank" class="demo-cont__credits-link">My codepen</a>
    <a href="https://twitter.com/NikolayTalanov" target="_blank" class="demo-cont__credits-link">My twitter</a>
    <h2 class="demo-cont__credits-heading">Based on</h2>
    <a href="https://dribbble.com/shots/2375246-Fashion-Butique-slider-animation" target="_blank" class="demo-cont__credits-link">Concept by Kreativa Studio</a>
    <h4 class="demo-cont__credits-blend">Global Blend Mode</h4>
    <div class="colorful-switch">
      <input type="checkbox" class="colorful-switch__checkbox js-activate-global-blending" id="colorful-switch-cb" />
      <label class="colorful-switch__label" for="colorful-switch-cb">
        <span class="colorful-switch__bg"></span>
        <span class="colorful-switch__dot"></span>
        <span class="colorful-switch__on">
          <span class="colorful-switch__on__inner"></span>
        </span>
        <span class="colorful-switch__off"></span>
      </label>
    </div>
  </div>
</div>

.fnc {

  // main variables, basically everything depends on $slidingAT
  $slidingAT: 1s;
  $slidingDelay: $slidingAT / 3 * 2;
  $maskAT: $slidingAT*0.7;
  $headingAT: $slidingAT * 1.5;
  $controlAT: $slidingAT/2;
  $easing: ease-in-out;
  $blendMode: luminosity;

  $contentLeft: 40%;
  $contentTop: 40%;
  
  $headingPadding: 30px;
  $headingFontSize: 100px;
  
  $maskTop: 15%;
  $maskRight: 100% - $contentLeft;
  $maskHeight: 67vh;
  $maskWidth: $maskHeight * 0.75;

  $black: #1F2833;

  /* you can add color names and their values here
  and then simply add classes like .m--blend-$colorName to .fnc-slide 
  to apply specific color for mask blend mode */
  $bgColors: (
    dark: lighten(#242424, 20%),
    green: #42605E,
    red: lighten(#6A0A0D, 10%),
    blue: #2D7791
  );

  &-slider {
    overflow: hidden;
    box-sizing: border-box;
    position: relative;
    height: 100vh;

    *, *:before, *:after {
      box-sizing: border-box;
    }

    &__slides {
      position: relative;
      height: 100%;
      transition: transform $slidingAT $slidingDelay;
    }
    
    // iterate through color map and set colors for specific classes
    @each $colorTheme, $bgColor in $bgColors {
      .m--blend-#{$colorTheme} {
        .fnc-slide__inner {
          background-color: lighten($bgColor, 20%);
        }

        .fnc-slide__mask-inner {
          background-color: $bgColor;
        }
      }

      .m--navbg-#{$colorTheme} {
        background-color: $bgColor;
      }
    }
  }

  &-slide {
    overflow: hidden;
    position: absolute;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    transform: translate3d(0,0,0);

    &.m--before-sliding {
      z-index: 2 !important;
      transform: translate3d(100%,0,0);
    }

    &.m--active-slide {
      z-index: 1;
      transition: transform $slidingAT $slidingDelay $easing;
      transform: translate3d(0,0,0);
    }

    &__inner {
      position: relative;
      height: 100%;
      background-size: cover;
      background-position: center top;
      transform: translate3d(0,0,0);

      .m--global-blending-active &,
      .m--blend-bg-active & {
        background-blend-mode: $blendMode;
      }

      .m--before-sliding & {
        transform: translate3d(-100%,0,0);
      }

      .m--active-slide & {
        transition: transform $slidingAT $slidingDelay $easing;
        transform: translate3d(0,0,0);
      }
    }

    &__mask {
      $activeDelay: $slidingAT + $slidingDelay/3;
      $xOffset: 200px;
      $yOffset: 0;
      $deg: 10deg;

      overflow: hidden;
      z-index: 1;
      position: absolute;
      right: $maskRight;
      top: $maskTop;
      width: $maskWidth;
      height: $maskHeight;
      margin-right: $headingPadding * -3;
      // This line basically does all magic with masking effect. Very simple and elegant. Webkit only atm.
      clip-path: polygon(0 0, 100% 0, 100% 100%, 0 100%, 0 0, 6vh 0, 6vh 61vh, 44vh 61vh, 44vh 6vh, 6vh 6vh);
      transform-origin: 50% 0;
      transition-timing-function: $easing;

      .m--before-sliding & {
        transform: rotate($deg*-1) translate3d($xOffset,0,0);
        opacity: 0;
      }

      .m--active-slide & {
        transition: transform $maskAT $activeDelay, opacity $maskAT/2 $activeDelay;
        transform: translate3d(0,0,0);
        opacity: 1;
      }

      .m--previous-slide & {
        transition: transform $maskAT $slidingDelay/2, opacity $maskAT/2 $maskAT/2 + $slidingDelay/2;
        transform: rotate($deg) translate3d($xOffset*-1,0,0);
        opacity: 0;
      }

      &-inner {
        z-index: -1;
        position: absolute;
        left: 50%;
        top: 50%;
        width: 100vw;
        height: 100vh;
        margin-left: -50vw;
        margin-top: -50vh;
        background-size: cover;
        background-position: center center;
        background-blend-mode: $blendMode;
        transform-origin: 50% (100vh - $maskHeight) / 2;
        transition-timing-function: $easing;

        .m--before-sliding & {
          transform: translateY($yOffset) rotate($deg) translateX($xOffset*-1) translateZ(0);
        }

        .m--active-slide & {
          transition: transform $maskAT $activeDelay;
          transform: translateX(0);
        }

        .m--previous-slide & {
          transition: transform $maskAT $slidingDelay/2;
          transform: translateY($yOffset) rotate($deg*-1) translateX($xOffset) translateZ(0);
        }
      }
    }

    &__content {
      z-index: 2;
      position: absolute;
      left: $contentLeft;
      top: $contentTop;
    }

    &__heading {
      margin-bottom: 10px;
      text-transform: uppercase;

      &-line {
        overflow: hidden;
        position: relative;
        padding-right: 20px;
        font-size: $headingFontSize;
        color: #fff;
        word-spacing: 10px;

        &:nth-child(2) {
          padding-left: $headingPadding;
        }

        .m--before-sliding & {
          transform: translateY(100%);
        }

        .m--active-slide & {
          transition: transform $headingAT $slidingDelay*1.5;
          transform: translateY(0);
        }

        .m--previous-slide & {
          transition: transform $headingAT;
          transform: translateY(-100%);
        }

        span {
          display: block;

          .m--before-sliding & {
            transform: translateY(-100%);
          }

          .m--active-slide & {
            transition: transform $headingAT $slidingDelay*1.5;
            transform: translateY(0);
          }

          .m--previous-slide & {
            transition: transform $headingAT;
            transform: translateY(100%);
          }
        }
      }
    }

    &__action-btn {
      $hoverAT: 0.3s;
      $fontSize: 20px;
      $vertPadding: 5px;
      $lineHeight: $fontSize + $vertPadding*2;

      position: relative;
      margin-left: 200px;
      padding: $vertPadding 15px;
      font-size: $fontSize;
      line-height: 1;
      color: transparent;
      border: none;
      text-transform: uppercase;
      background: transparent;
      cursor: pointer;
      text-align: center;
      outline: none;

      span {
        position: absolute;
        left: 0;
        top: 0;
        width: 100%;
        height: 100%;
        perspective: 1000px;
        transform-style: preserve-3d;
        transition: transform $hoverAT;
        transform-origin: 50% 0;
        line-height: $lineHeight;
        color: #fff;

        &:before {
          content: "";
          position: absolute;
          left: 0;
          top: 0;
          width: 100%;
          height: 100%;
          border: 2px solid #fff;
          border-top: none;
          border-bottom: none;
        }

        &:after {
          content: attr(data-text);
          position: absolute;
          left: 0;
          top: 0;
          width: 100%;
          height: 100%;
          line-height: $lineHeight;
          background: $black;
          opacity: 0;
          transform-origin: 50% 0;
          transform: translateY(100%) rotateX(-90deg);
          transition: opacity $hoverAT/2 $hoverAT/2;
        }
      }

      &:hover span {
        transform: rotateX(90deg);

        &:after {
          opacity: 1;
          transition: opacity $hoverAT/2;
        }
      }
    }
  }

  &-nav {
    z-index: 5;
    position: absolute;
    right: 0;
    bottom: 0;

    &__bgs {
      z-index: -1;
      overflow: hidden;
      position: absolute;
      left: 0;
      top: 0;
      width: 100%;
      height: 100%;
    }

    &__bg {
      position: absolute;
      left: 0;
      top: 0;
      width: 100%;
      height: 100%;

      &.m--nav-bg-before {
        z-index: 2 !important;
        transform: translateX(100%);
      }

      &.m--active-nav-bg {
        z-index: 1;
        transition: transform $slidingAT $slidingDelay;
        transform: translateX(0);
      }
    }
    
    &__controls {
      font-size: 0;
    }

    &__control {
      $controlWidth: 100px;

      overflow: hidden;
      position: relative;
      display: inline-block;
      vertical-align: top;
      width: $controlWidth;
      height: 50px;
      font-size: 14px;
      color: #fff;
      text-transform: uppercase;
      background: transparent;
      border: none;
      outline: none;
      cursor: pointer;
      transition: background-color $controlAT;

      &.m--active-control {
        background: $black;
      }

      &-progress {
        position: absolute;
        left: 0;
        bottom: 0;
        width: 100%;
        height: 2px;
        background: #fff;
        transform-origin: 0 50%;
        transform: scaleX(0);
        transition-timing-function: linear !important;

        .m--with-autosliding .m--active-control & {
          transform: scaleX(1);
        }

        .m--prev-control & {
          transform: translateX(100%);
          transition: transform 0.5s !important;
        }

        .m--reset-progress & {
          transform: scaleX(0);
          transition: transform 0s 0s !important;
        }

        .m--autosliding-blocked & {
          transition: all 0s 0s !important;
          transform: scaleX(0) !important;
        }
      }
    }
  }

}


/* NOT PART OF COMMON SLIDER STYLES */
$font: 'Open Sans', Helvetica, Arial, sans-serif;
$creditsAT: 0.7s;
$creditsWidth: 400px;

body {
  margin: 0;
}

.demo-cont {
  overflow: hidden;
  position: relative;
  height: 100vh;
  perspective: 1500px;
  background: #000;
  
  &__credits {
    box-sizing: border-box;
    overflow-y: auto;
    z-index: 1;
    position: absolute;
    right: 0;
    top: 0;
    width: $creditsWidth;
    height: 100%;
    padding: 20px 10px 30px;
    background: #303030;
    font-family: $font;
    color: #fff;
    text-align: center;
    transition: transform $creditsAT;
    transform: translate3d(100%,0,0) rotateY(-45deg);
    will-change: transform;
    
    .credits-active & {
      transition: transform $creditsAT $creditsAT/3;
      transform: translate3d(0,0,0);
    }
    
    *, *:before, *:after {
      box-sizing: border-box;
    }
    
    &-close {
      position: absolute;
      right: 20px;
      top: 20px;
      width: 28px;
      height: 28px;
      cursor: pointer;
      
      &:before,
      &:after {
        content: "";
        position: absolute;
        left: 0;
        top: 50%;
        width: 100%;
        height: 2px;
        margin-top: -1px;
        background: #fff;
      }
      &:before {
        transform: rotate(45deg);
      }
      &:after {
        transform: rotate(-45deg);
      }
    }
    
    &-heading {
      text-transform: uppercase;
      font-size: 40px;
      margin-bottom: 20px;
    }
    
    &-img {
      display: block;
      width: 60%;
      margin: 0 auto 30px;
      border-radius: 10px;
    }
    
    &-name {
      margin-bottom: 20px;
      font-size: 30px;
    }
    
    &-link {
      display: block;
      margin-bottom: 10px;
      font-size: 24px;
      color: #fff;
    }
    
    &-blend {
      font-size: 30px;
      margin-bottom: 10px;
    }
  }
}

.example-slider {
  z-index: 2;
  transform: translate3d(0,0,0);
  transition: transform $creditsAT;
  
  .credits-active & {
    transform: translate3d($creditsWidth*-1,0,0) rotateY(10deg) scale(0.9);
  }

  .fnc-slide {

    &-1 {
      .fnc-slide__inner,
      .fnc-slide__mask-inner {
        background-image: url('https://s3-us-west-2.amazonaws.com/s.cdpn.io/142996/blackwidow.jpg');
      }
    }
    &-2 {
      .fnc-slide__inner,
      .fnc-slide__mask-inner {
        background-image: url('https://s3-us-west-2.amazonaws.com/s.cdpn.io/142996/captainamerica.jpg');
      }
    }
    &-3 {
      .fnc-slide__inner,
      .fnc-slide__mask-inner {
        background-image: url('https://s3-us-west-2.amazonaws.com/s.cdpn.io/142996/ironman-alt.jpg');
      }

      .fnc-slide__inner:before {
        content: "";
        position: absolute;
        left: 0;
        top: 0;
        width: 100%;
        height: 100%;
        background: rgba(255,255,255,0.1);
      }
    }
    &-4 {
      .fnc-slide__inner,
      .fnc-slide__mask-inner {
        background-image: url('https://s3-us-west-2.amazonaws.com/s.cdpn.io/142996/thor.jpg');
      }

      .fnc-slide__inner:before {
        content: "";
        position: absolute;
        left: 0;
        top: 0;
        width: 100%;
        height: 100%;
        background: rgba(0,0,0,0.2);
      }
    }
  }

  .fnc-slide__heading,
  .fnc-slide__action-btn,
  .fnc-nav__control {
    font-family: $font;
  }
}

/* COLORFUL SWITCH STYLES 
   ORIGINAL DEMO - https://codepen.io/suez/pen/WQjwOb */
$w: 180px;
$_baseW: 280;
$h: $w * 120 / $_baseW;
$br: $w * 50 / $_baseW;
$outerOffset: 5px;
$animTime: 0.5s;
$dotS: $w * 8 / $_baseW;
$dotLeft: $w * 204 / $_baseW;
$dotLeftOffset: $w * -125 / $_baseW;
$offS: $w * 64 / $_baseW;
$onLeft: $w * 162 / $_baseW;
$onTop: $w * 35 / $_baseW;
$onWidth: $w * 30 / $_baseW;
$onHeight: $w * 56 / $_baseW;
$cubIn: cubic-bezier(.52,-0.96,.51,1.28);
$cubOut: cubic-bezier(.67,-0.16,.47,1.61);

@mixin switchOn() {
  .colorful-switch__checkbox:checked ~ .colorful-switch__label & {
    @content;
  }
}

.colorful-switch {
  position: relative;
  width: $w;
  height: $h;
  margin: 0 auto;
  border-radius: $br;
  background: #cfcfcf;

  &:before {
    content: "";
    z-index: -1;
    position: absolute;
    left: -$outerOffset;
    top: -$outerOffset;
    width: $w + $outerOffset*2;
    height: $h + $outerOffset*2;
    border-radius: $br + $outerOffset;
    background: #314239;
    transition: background-color 0.3s;
  }

  &:hover:before {
    background: #4C735F;
  }

  &__checkbox {
    z-index: -10;
    position: absolute;
    left: 0;
    top: 0;
    opacity: 0;
  }

  &__label {
    z-index: 1;
    overflow: hidden;
    position: absolute;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    border-radius: $br;
    cursor: pointer;
  }

  &__bg {
    position: absolute;
    left: 0;
    top: 0;
    width: $w * 3;
    height: 100%;
    background: linear-gradient(90deg, #14DCD6 0, #10E7BD $w, #EF9C29 $w*2, #E76339 100%);
    transition: transform $animTime;
    transform: translate3d($w*-2,0,0);

    @include switchOn {
      transform: translate3d(0,0,0);
    }
  }

  &__dot {
    position: absolute;
    left: $dotLeft;
    top: 50%;
    width: $dotS;
    height: $dotS;
    margin-left: $dotS/-2;
    margin-top: $dotS/-2;
    border-radius: 50%;
    background: #fff;
    transition: transform $animTime;
    transform: translate3d(0,0,0);

    @include switchOn {
      transform: translate3d($dotLeftOffset,0,0);
    }
  }

  &__on {
    position: absolute;
    left: $onLeft;
    top: $onTop;
    width: $onWidth;
    height: $onHeight;
    transition: transform $animTime;
    transform: translate3d(0,0,0);

    @include switchOn {
      transform: translate3d($dotLeftOffset,0,0);
    }

    &__inner {
      position: absolute;
      width: 100%;
      height: 100%;
      transition: transform $animTime/2 0s $cubIn;
      transform-origin: 100% 50%;
      transform: rotate(45deg) scale(0) translateZ(0);

      @include switchOn {
        transition: transform $animTime/2 $animTime/2 $cubOut;
        transform: rotate(45deg) scale(1) translateZ(0);
      }

      &:before,
      &:after {
        content: "";
        position: absolute;
        border-radius: $dotS/2;
        background: #fff;
      }
      &:before {
        left: 0;
        bottom: 0;
        width: 100%;
        height: $dotS+1px;
      }
      &:after {
        right: 0;
        top: 0;
        width: $dotS+1px;
        height: 100%;
      }
    }
  }

  &__off {
    position: absolute;
    left: $dotLeft;
    top: 50%;
    width: $offS;
    height: $offS;
    margin-left: $offS/-2;
    margin-top: $offS/-2;
    transition: transform $animTime;
    transform: translate3d(0,0,0);

    @include switchOn {
      transform: translate3d($dotLeftOffset,0,0);
    }

    &:before,
    &:after {
      content: "";
      position: absolute;
      left: 0;
      top: 50%;
      width: 100%;
      height: $dotS;
      margin-top: $dotS/-2;
      border-radius: $dotS/2;
      background: #fff;
      transition: transform $animTime/2 $animTime/2;

      @include switchOn {
        transition-delay: 0s;
      }
    }
    &:before {
      transform: rotate(45deg) scaleX(1) translateZ(0);

      @include switchOn {
        transform: rotate(45deg) scaleX(0) translateZ(0);
      }
    }
    &:after {
      transition-timing-function: $cubOut;
      transform: rotate(-45deg) scaleX(1) translateZ(0);

      @include switchOn {
        transition-timing-function: ease;
        transform: rotate(-45deg) scaleX(0) translateZ(0);
      }
    }
  }
}

View Compiled

(function() {

  var $$ = function(selector, context) {
    var context = context || document;
    var elements = context.querySelectorAll(selector);
    return [].slice.call(elements);
  };

  function _fncSliderInit($slider, options) {
    var prefix = ".fnc-";

    var $slider = $slider;
    var $slidesCont = $slider.querySelector(prefix + "slider__slides");
    var $slides = $$(prefix + "slide", $slider);
    var $controls = $$(prefix + "nav__control", $slider);
    var $controlsBgs = $$(prefix + "nav__bg", $slider);
    var $progressAS = $$(prefix + "nav__control-progress", $slider);

    var numOfSlides = $slides.length;
    var curSlide = 1;
    var sliding = false;
    var slidingAT = +parseFloat(getComputedStyle($slidesCont)["transition-duration"]) * 1000;
    var slidingDelay = +parseFloat(getComputedStyle($slidesCont)["transition-delay"]) * 1000;

    var autoSlidingActive = false;
    var autoSlidingTO;
    var autoSlidingDelay = 5000; // default autosliding delay value
    var autoSlidingBlocked = false;

    var $activeSlide;
    var $activeControlsBg;
    var $prevControl;

    function setIDs() {
      $slides.forEach(function($slide, index) {
        $slide.classList.add("fnc-slide-" + (index + 1));
      });

      $controls.forEach(function($control, index) {
        $control.setAttribute("data-slide", index + 1);
        $control.classList.add("fnc-nav__control-" + (index + 1));
      });

      $controlsBgs.forEach(function($bg, index) {
        $bg.classList.add("fnc-nav__bg-" + (index + 1));
      });
    };

    setIDs();

    function afterSlidingHandler() {
      $slider.querySelector(".m--previous-slide").classList.remove("m--active-slide", "m--previous-slide");
      $slider.querySelector(".m--previous-nav-bg").classList.remove("m--active-nav-bg", "m--previous-nav-bg");

      $activeSlide.classList.remove("m--before-sliding");
      $activeControlsBg.classList.remove("m--nav-bg-before");
      $prevControl.classList.remove("m--prev-control");
      $prevControl.classList.add("m--reset-progress");
      var triggerLayout = $prevControl.offsetTop;
      $prevControl.classList.remove("m--reset-progress");

      sliding = false;
      var layoutTrigger = $slider.offsetTop;

      if (autoSlidingActive && !autoSlidingBlocked) {
        setAutoslidingTO();
      }
    };

    function performSliding(slideID) {
      if (sliding) return;
      sliding = true;
      window.clearTimeout(autoSlidingTO);
      curSlide = slideID;

      $prevControl = $slider.querySelector(".m--active-control");
      $prevControl.classList.remove("m--active-control");
      $prevControl.classList.add("m--prev-control");
      $slider.querySelector(prefix + "nav__control-" + slideID).classList.add("m--active-control");

      $activeSlide = $slider.querySelector(prefix + "slide-" + slideID);
      $activeControlsBg = $slider.querySelector(prefix + "nav__bg-" + slideID);

      $slider.querySelector(".m--active-slide").classList.add("m--previous-slide");
      $slider.querySelector(".m--active-nav-bg").classList.add("m--previous-nav-bg");

      $activeSlide.classList.add("m--before-sliding");
      $activeControlsBg.classList.add("m--nav-bg-before");

      var layoutTrigger = $activeSlide.offsetTop;

      $activeSlide.classList.add("m--active-slide");
      $activeControlsBg.classList.add("m--active-nav-bg");

      setTimeout(afterSlidingHandler, slidingAT + slidingDelay);
    };



    function controlClickHandler() {
      if (sliding) return;
      if (this.classList.contains("m--active-control")) return;
      if (options.blockASafterClick) {
        autoSlidingBlocked = true;
        $slider.classList.add("m--autosliding-blocked");
      }

      var slideID = +this.getAttribute("data-slide");

      performSliding(slideID);
    };

    $controls.forEach(function($control) {
      $control.addEventListener("click", controlClickHandler);
    });

    function setAutoslidingTO() {
      window.clearTimeout(autoSlidingTO);
      var delay = +options.autoSlidingDelay || autoSlidingDelay;
      curSlide++;
      if (curSlide > numOfSlides) curSlide = 1;

      autoSlidingTO = setTimeout(function() {
        performSliding(curSlide);
      }, delay);
    };

    if (options.autoSliding || +options.autoSlidingDelay > 0) {
      if (options.autoSliding === false) return;
      
      autoSlidingActive = true;
      setAutoslidingTO();
      
      $slider.classList.add("m--with-autosliding");
      var triggerLayout = $slider.offsetTop;
      
      var delay = +options.autoSlidingDelay || autoSlidingDelay;
      delay += slidingDelay + slidingAT;
      
      $progressAS.forEach(function($progress) {
        $progress.style.transition = "transform " + (delay / 1000) + "s";
      });
    }
    
    $slider.querySelector(".fnc-nav__control:first-child").classList.add("m--active-control");

  };

  var fncSlider = function(sliderSelector, options) {
    var $sliders = $$(sliderSelector);

    $sliders.forEach(function($slider) {
      _fncSliderInit($slider, options);
    });
  };

  window.fncSlider = fncSlider;
}());

/* not part of the slider scripts */

/* Slider initialization
options:
autoSliding - boolean
autoSlidingDelay - delay in ms. If audoSliding is on and no value provided, default value is 5000
blockASafterClick - boolean. If user clicked any sliding control, autosliding won't start again
*/
fncSlider(".example-slider", {autoSlidingDelay: 4000});

var $demoCont = document.querySelector(".demo-cont");

[].slice.call(document.querySelectorAll(".fnc-slide__action-btn")).forEach(function($btn) {
  $btn.addEventListener("click", function() {
    $demoCont.classList.toggle("credits-active");
  });
});

document.querySelector(".demo-cont__credits-close").addEventListener("click", function() {
  $demoCont.classList.remove("credits-active");
});

document.querySelector(".js-activate-global-blending").addEventListener("click", function() {
  document.querySelector(".example-slider").classList.toggle("m--global-blending-active");
});

This Pen is owned by Nikolay Talanov on CodePen.

See more by @suez on CodePen

External CSS

https://fonts.googleapis.com/css?family=Open+Sans

External JavaScript

This Pen doesn't use any external JavaScript resources.